On the background of the recent demand for size reduction of semiconductor device, copper having small resistance has been used as an wiring material. Commonly, a copper wiring is formed such that a groove is formed in an insulating film formed on a surface of a substrate, the groove is filled with copper, and thereafter extra copper is pruned by Chemical Mechanical Polishing (CMP). The substrate polished by the CMP is cleaned by wet cleaning and then dried. The insulating film filled with copper is formed using a material (a low-k film) having a low k value (relative dielectric constant) in order to reduce capacitance of a capacitor formed between wirings. Since the low-k film is hydrophobic, a water film on a substrate is likely to be divided at the time of cleaning after polishing, and if drying is performed in a state in which a water film is divided, a defect such as a watermark is likely to occur.
Under the circumstances, as a drying method that is effective for defect occurrence suppression, there is a method (hereinafter, referred to “single wafer IPA drying”) of single wafer processing in which a liquid flow of a rinse agent for drying is supplied from a rinse agent nozzle to a rotating substrate, a liquid film covering the entire surface of the substrate is formed, a gas flow for drying containing isopropyl alcohol (IPA) reducing a surface tension of the rinse agent is supplied from a drying gas nozzle to the inside of the liquid flow, the rinse agent nozzle and the drying gas nozzle are moved from the center of the rotating substrate toward an outer circumference, the rinse agent is moved to the outer circumference side by centrifugal force and Marangoni force, a dried area on the substrate is gradually spread to the outer circumference, and the entire surface of the substrate is finally dried.
In the single wafer IPA drying, the rinse agent is spread toward the outer circumference of the substrate by the centrifugal force. At the same time, by increasing surface tension of an edge or an interface of the rinse agent (hereinafter referred to as “rinse edge”) outward by the Marangoni effect caused by the IPA, the rinse edge is moved toward the outer circumference of the substrate.
However, in the single wafer IPA drying, if a drying condition such as a supply amount of the rinse agent or a moving speed toward the outer circumference of the rinse agent nozzle and the drying gas nozzle is inappropriate for a moving speed of the substrate surface by rotation of the substrate, the single wafer IPA drying is not properly performed, and a defect is caused by a watermark or a residual foreign substance. Particularly, when a substrate has a large diameter, for example, since a difference in a relative moving speed of the substrate surface between at a location near the center and at a location near the outer circumference regarding the rinse agent nozzle and the drying gas nozzle is increased, it is difficult to perform the excellent single wafer IPA drying by moving the rinse edge from the center to the outer circumference while keeping the throughput as high as possible.
It is desired to provide a substrate drying apparatus, a control program, and a substrate drying method, which are capable of suppressing the occurrence of a defect by performing the excellent single wafer IPA drying.
A substrate drying apparatus according to an embodiment includes a substrate rotating mechanism configured to rotate a substrate within a horizontal plane, a rinse agent nozzle configured to eject a rinse agent to the substrate while moving away from a center of the substrate relative to the substrate rotated by the substrate rotating mechanism, a drying gas nozzle configured to spout a drying gas to the substrate while moving away from the center of substrate relative to the substrate rotated by the substrate rotating mechanism with movement of the rinse agent nozzle, a sensor configured to sense a surface of the substrate around an rinse edge of the rinse agent by moving away from the center of the substrate with movement of the rinse agent nozzle and the drying gas nozzle, and a control unit configured to control a drying condition based on the sensing result of the sensor such that the rinse edge is spread on the surface of the substrate toward an outer circumference of the substrate by the rinse agent and the drying gas.
A substrate drying apparatus according to another aspect includes a substrate rotating mechanism configured to rotate a substrate within a horizontal plane, a rinse agent nozzle configured to eject a rinse agent to the substrate while moving away from a center of the substrate relative to the substrate rotated by the substrate rotating mechanism, a drying gas nozzle configured to spout a drying gas to the substrate while moving away from the center of substrate relative to the substrate rotated by the substrate rotating mechanism with movement of the rinse agent nozzle, a sensor configured to sense a surface of the substrate while moving together with the rinse agent nozzle, and a control unit configured to control a drying condition based on the sensing result of the sensor.
Further, a substrate drying apparatus according to another aspect includes a substrate rotating mechanism configured to rotate a substrate within a horizontal plane, a rinse agent nozzle configured to eject a rinse agent to the substrate while moving away from a center of the substrate relative to the substrate rotated by the substrate rotating mechanism, a drying gas nozzle configured to spout a drying gas to the substrate while moving away from the center of substrate relative to the substrate rotated by the substrate rotating mechanism with movement of the rinse agent nozzle, and a control unit configured to control the rinse agent nozzle such that an ejection amount of the rinse agent is increased as the rinse agent nozzle gets away from the center of the substrate.
A substrate drying method according to an embodiment includes rotating a substrate within a horizontal plane, ejecting a rinse agent from a rinse agent nozzle to the substrate while moving the rinse agent nozzle away from a center of the substrate, spouting a drying gas from a drying gas nozzle to the substrate while moving the drying gas nozzle away from the center of substrate with movement of the rinse agent nozzle, sensing a surface of the substrate around an rinse edge of the rinse agent by moving away from the center of the substrate with movement of the rinse agent nozzle and the drying gas nozzle, and controlling a drying condition based on the sensing result such that the rinse edge is spread on the surface of the substrate toward an outer circumference of the substrate by the rinse agent and the drying gas.
A storage medium according to an embodiment stores the following control program in a non-transitory manner; the control program controls a substrate drying apparatus including a substrate rotating mechanism configured to rotate a substrate within a horizontal plane, a rinse agent nozzle configured to eject a rinse agent to the substrate while moving away from a center of the substrate relative to the substrate rotated by the substrate rotating mechanism, a drying gas nozzle configured to spout a drying gas to the substrate while moving away from the center of substrate relative to the substrate rotated by the substrate rotating mechanism with movement of the rinse agent nozzle, a sensor configured to sense a surface of the substrate around an rinse edge of the rinse agent by moving away from the center of the substrate with movement of the rinse agent nozzle and the drying gas nozzle, wherein the control program controls a drying condition based on the sensing result of the sensor such that the rinse edge is spread on the surface of the substrate toward an outer circumference of the substrate by the rinse agent and the drying gas.